Inadequate or disrupted sleep in childhood is highly predictive for the later development of anxiety disorders and depression. The combined societal cost of these disorders is estimated above $120 billion annually, underscoring a need for early identification and effective intervention methods. Experimental data in adults indicate a critical link between sleep disruption and affective disorders to exist in the maladaptive processing of emotion. In order to delineate specific risk mechanisms however, understanding of these relationships in childhood when sleep and emotion regulatory systems are developing is essential. An increased need for sleep and greater brain plasticity during the childhood years also suggest a 'window' of opportunity for intervention to exist. This study will use an experimental sleep restriction paradigm to identify cognitive, behavioral and physiologic mechanisms of affective risk among 50 pre-adolescent children, ages 7 to 11 years. We will include children with a range of (subclinical) anxious and depressive symptoms in order to determine whether certain affective profiles potentiate greater vulnerability in conjunction with sleep disruption than others. All children will undergo comprehensive psychosocial evaluation, in-home polysomnography and one week of actigraphy. A battery of novel tasks assessing discrete aspects of emotional processing (appraisal, reactivity and regulation) will be completed following a week of normal sleep and again after a 2-night sleep restriction protocol. In addition, because high-risk trajectories are characterized by the presence and interaction of multiple risk and protective factors, we will investigate the potential moderating influence of several theoretically-relevant cognitive and biological variables. In particular, children's cognitive response style, typical sleep onset latency, and preferred sleep pattern (i.e., chronotype) will be investigated as potential moderators of emotional outcomes. Finally, we will explore relationships among sleep architecture, EEG spectral power (during normal and recovery sleep) and emotional outcomes in order to identify potential neurobiological markers of affective response to sleep loss in childhood. The long term goal of this study which aligns with both NIMH's Strategic Plan and Research Domain Criteria (RDoC) is to advance existing prevention/early intervention protocols beyond non- specific targets toward more explicit mechanisms of risk.